Apparatus for making sheet glass



June 29 1926.

F. GELSTHARP APPARATUS FOR MAKING SHEETGLASS Filed Oct. 7, 1924 5 Sheets-Sheet 1 June '29 1926. 1,590,820

. F. GELSTHARP APPARATUS FOR MAKING SHEET GLASS Filed Oct. "7. 1924 5 Sheets-Sheet 2 lNt/E/VTOR June 29 1926.

' F. GELSTHARP APPARATUS FOR MAKING SHEET GISASS Filed 061. 7, 1924 5 Sheets-Sheet 3 //v VEN 70/ Patented Elaine W26.

PLATE GLASS COMPANY, A COBFOBATION F PENNSYLVANEA.

APPARATUS FOR MAKING.- SHEET GLASS.

Application filed tlctober 7, 1924;. Serial Ito. Ti l-2,182.

The invention relates to an apparatus for making sheet glass continuously from a tank. It has for its principal objects the provision of an improved apparatus, wherein the contact ot the molten glass with the clay work at the end of the tank is reduced to a minimum, thus reducing the contamina tion of the glass tending to cause string and reamto a minimum; and wherein the lengthening. of any bubbles in the glass incident to the rolling and sizing action is reduced, so that the visibility of such bubbles in the finished product is made as slight as possible, a round or slightly elongated bubble being much less noticeable than one which is stretched to a length several times that of the original one. Certain embodiments of the invention are illustrated in the accompanying drawings wherein:

Figure 1 is a longitudinal vertical section through the apparatus on the line l--ll of Fig. 2. Fig. 2 is a transverse section on the line H-H of Fig. 1. Fig. 3 is a horizontal section on a reduced scale on the line lll-lll of Fig. 1. And Figs. 5 and 6 are longitudinal vertical sections through moditied embodiments of the invention.

Briefly stated the apparatus consists in means for flowinga body of glass laterally over a dam or lip or through a slot or openin in the side wall of a melting tank, a ta le for receiving the glass where it piles up and is spread out in a layer of much greater width than the width of the outlet W slot, and a pair of sizing rolls at the forward 'end of the table.

This procedure involved in the use of this apparatus tends to prevent an elongation of any bubbles in the glass, which the rolling would otherwise tend to pro duce since the lateral spreading of the glass tends to widen the bubbles laterally and thus counteracts the tendency to lengthen them in the direction in which the sur- 5 :taces of the rolls are moving, and since the surface glass carrying the bubbles stiffens,

as later explained, before reaching the rolls. Further, since the width of the outlet slot is only a traction of the'width of the tinished sheet, the area of clay (constituting the periphery of the slot and contacting with the glass) is 0111 a traction of what it would be, if the widtot' the slot approximated that of the finished sheet. The spreading action of the sheet may be promoted by having the surface of the table slant downwardly from its longitudinal center line to its side edges, and this spreading action can also be adjusted by regulating the feed or temperature or both of molten glass to the table in its relation to the speed of rotation of the sizing rolls, and by shifting the angle of the table about an axis of rotation transverse to the. direction of movement of the glass sheet. An alternative means of creating the spread is to tilt the table down from the rolls toward the tank and providing it with a water cooled back flange to support the mass of glasswhich is forced to spread sidewise.

Referring to the drawings, lis the outlet end of a melting tank, preferably of the well known regenerator type, having an outlet 2 below the level of the glass in the tank, and

contracted by means or the. gate 3, supported 7 upon suitable means 4 for adjusting its 'vertical position. Back of the regulating gate is a water cooled cut oil gate 5, also mounted for vertical movement upon the chains 6 and adapted to entirely cut oil the supply of glass in case of emergencies or in case it becomes necessary to shut down the tank for any considerable time for repla-eeu'ients or repairs. Back of the gate 5 is a shade 7 of clay supported by the chains 8, which may be lowered to the surface of the glass when the gate 5 is lowered, so that the glass back of the gate will not be unduly chilled by the water cooled gate during the shut down. Forward of the control gate is another water cooled gate 9 or cut oil supported for vertical movement by the chains 10 and designed to be employed for quick and short stops. Both water cooled gates are provided with inlet and outlet pipes so that a flow of cooling water may be circulated through them.

1F orward oi the outlet 2 in position to re ceive the glass, is the table 11, which is relatively short length, as compared with its width, as'will be seen by reference to Figs. 1 and 2. The table is preferably made hollow and with a polished surface, and is water cooled by the provision of inlet and outlet connections to provide for a continuous circulation of water therethrough. l't is preterably pivoted at its forward end as indicated at 12, and its rear end is provided witha pair of screw gacks 13, 13, so that the angle till of the table may be adjusted to meet requirements. This table is mounted upon the truck 14, in turn carried by the track 15.

Also carried by the truck in advance of the table are the sizing rolls 15 and 16, which rolls are hollow and water cooled, by means of Suitable inlet and outlet connections. The rolls are connected at their ends to the tumble shafts 17 and 18, journaled at their outer ends in the standard 19, and driven by the reducing gearing comprising the worm wheels 20 and 21 on the shafts 17 and 18 and the worms 22 and 23 on the vertical shaft 24. The vertical shaft 23 is driven from the electric motor 25 through the intermediary of a gear reduction in the casing 26, and the worm wheel and worm 27 and 28, the worm wheel being carried by the vertical shaft 24 and the worm being carried by the horizontal shaft 29 leading from the gear reduction in the casing 26. The motor and reduction gearing are carried by the truck, so that when replacements orrepairs are required on the front of the furnace or in any of the mechanism carried by the truck, the truck can be'moved later ally to give the necessary working space and get the parts away from the heat of the tank. The movement of the truck may be conveniently secured by rotating the shaft 30 which carries a worm 31 meshing with a worm wheel 32 carried by one of the axles 33 of the truck, a handle 34 being provided for turning the shaft 30.

The width of the outlet slot is preferably only from one-sixth to one-twelfth the width of the table 11, and sizing rolls 15 and 16, so that in operation the molten glass piles up on the table back of the roll and spreads laterally to a width slightly less than the width of the table. In order to promote this spreading action, the table may be crowned, so that its upper surface slopesdown slightly from its rear to its forward ends and also slopes down from its longitudinal center line to its side edges as indicated in Fig. 2. The amount of spreading also depends on the relative amount of feed and temperature through the outlet 2 as compared with the speed of withdrawal by the rolls 15 and 16, and either or both of these factors are subject to regulation.

Similarly, the angle of the table affects the amount of spreading and this is adjusted by means of the screw jacks 13, 13. The matter of temperature also has an effect on the movement of the glass over the table and this may be controlled by regulating the initial temperature of the glass in the tank and by the application of heat or chilling action to the glass on the table. The glass may be chilled more or less by regulating the flow of water through the table, or it may be heated by the burners 35, 36 and 37, the burner 35 extending clear across the width of the table, while the burner 37 extends across the width of the stream of glass flowing from the outlet 2. The burner 37 also serves to regulate the extent to which the glass flows to the rear as indicated at 38. Under some conditions, air may be supplied through the pipe 37 instead of gas, so that a cooling effect is produced. The burners 36 are applied only at the edges of the layer of glass upon the table and control in a measure the spreading action and prevent such edges from cooling too. rapidly and causing cracks in the edges of the sheet.

The spreading action on the table tends to spread laterally any bubbles in the sheet, this, in connection with other factors later pointed out counteracting the tendency of the sizing rolls to elongate such bubbles so that they are rendered more noticeable in the finished product. A further advantage is involved in having the outlet slot 2 of narrow width, as compared with the finished sheet, in that the area of clay over which the glass flows is reduced to a minimum, thus reducing to a minimum the contamination of the glass incident to the con-,-

-tact with the clay. The table 11 is referred to in the claims as stationary (although it is adjustable) to distinguish from the type heretofore contemplated in which an enclless carrier is employed, so that the surface receiving the glass moves along with it.

Forward of the rolls 15 and 16 is an apron carried by the truck and with rolls 40 having sprockets at their ends driven by the chain 39. The rolls carry the glass sheet 41 continuously into the leer 42. This apron and rolls are enclosed in clay walls o prevent too rapid cooling of the glass, 43 being the floor which protects the metal work of the truck and 44 being a portable cover which may be removed by means of the connections 45 engaging a suitable overhead crane. The space inside the clay Work and the leer may be heated by gas burners projecting through the openings 46. The leer ma be of any approved construction but pre erably is of the roller type employ ing the rolls 47 for carrying the glass continuously forward while being gradually annealed and cooled. The rolls 47, like the rolls 40 are provided at their ends with sprockets and are driven by a chain 48.

.Figure 4 illustrates a modification in of Fig. 1) being dispensed with. in this construction, the angle of inclination of the table 52 is also increased.

Fig. 6 illustrates still another modification, in which the water cooled table 53 is inclined downwardly from the rolls back toward the tank, and a flange 54 prevents the glass from flowing off the table to the rear. In other respects, the construction is similar to that of Fig. 5. This is the pre terred construction.

In all the forms of the invention, the tables employed are polished so as apply a smoothing action to the lower surface of the sheet drawn thereover, so that the grinding required on such side is reduced to a minimum. Further, the traction of the rolls 15 and 16, continuously and progressively, removes the bottom chilled surface or skin, as itis formed, so that at no time is stag nant glass left upon the table, thus preventing any tendency to devitrification. The chilled skin insulates, in a large measure, the molten glass above it, the chilled outside surfaces being removed automatically as the sheet is formed. If it were not for this action, it would not be practicable to pour the glass upon a stationary table in front of the rolls and continue to form a sheet from it. The lateral flow of the glass carries the major portion of any bubbles rising to the surface, and any surface impurities, to the sides of the sheet Where they are least damagingto the value of the fin ished product, and the glass is so cooled and hardened in its surface portions by the time they pass between the rolls that the bubbles contained therein are only slightly flattened or elongated by the sizing action. This is perhaps the most important factor in the operation tending to prevent a stretching of the bubbles. In the practice of the process, the fluid surface glass in the body behind the rolls flows to the rear and sidewise from the longitudinal center line of the glass (see arrows Fig. 3,) and around its side edges to the lower surface of the lass, so

that a large proportion of any bu bles or impurities, are incorporated into the lower side of the sheet formed, and closely adjacent to or at such surface. This lower surface skin is very stifi, due to the heavy chill from the table, so that the rolling ac tion cannot stretch it (and the bubbles therein embedded), and the grinding operation which follows, is efitective to eliminate most of these defects from the finished product.

What I claim is:

1. ln apparatus for the manufacture of sheet glass, the combination with a tank or receptacle provided with an outlet so as to permit the dischar e therethrough of molten glass under the ead pressure in the tank, a stationary spreading table in posi sition to receive the molten glass from saidoutlet oi'a width much greater than that of said outlet, a pair of sizing rolls at the torward'end of the table of a length greater than the width of said outlet, and a leer in advance of said rolls.

3. In apparatus for the manufacture of sheet glass, the combination with a, tank or receptacle provided with an outlet so as to permit the discharge therethrough of molten glass under the head pressure in the tank, a stationary spreading table in. position to receive the molten glass from said outlet of a width much greater than that of said outlet, a pair of sizing rolls at the forward end of the table of a length greater than the width of said outlet, means for 'cOOliIflg; said table and a leer in advance or" said rolls.

d. in apparatus for the mai'iuiacture o't sheet glass, the combination with a tank or receptacle provided with an outlet so as to permit the discharge therethrough of molten glass under the head pressure in the tank, astationary inclined spreading table in line with said outlet below the level thereoi of a width. greater tl its lengtll and very substantially greater that or the outlet, a pair of sizingrolls at the for ward end of the table, and a leer in advance of said rolls.

5. In apparatus for the manufacture of sheet glass, the combination with a tank or receptacle provided with an outlet so as to permit the discharge therethrough o t molten glass under the head pressure in the tank, stationar spreading table in posh tion to receive themolten glass from said outlet oi a width much greater than that of said outlet, a; pair ot sizing rolls at the forward end. oil the table of a length greater than the width ort said outlet, means for acljusting the angle oat inclination of the table with respect to the rolls to regulate the spreading action oi the molten glass on the table, and a leer in advance of said rolls.

6. In apparatus for the manufacture oi sheet glass, the combination with a tank or receptacle provided with an outlet so as to permit the discharge therethrough of molten glass under the head pressure in the tank, a laterally extending spreading table below the level oil: said outlet, in position re.

lltlll ltlfi llld,

ltd)

llfltl me eee mote the spreading of the molten glass preiiminary to its entrance between said rolls.

In testimony whereof, I have hereunto subscribed my name this 23rd day of Sept,

FREDERICK GELSTHARP. 

